1. Field of the Invention:
The invention concerns a method of making aluminum-base metal clad, zinc-rich metal coated, steel sheet.
2. Description of the Prior Art:
Aluminum coated galvanized steel laminates are described. See U.S. Pat. Nos. 2,490,978 (OSTERHELD), 3,475,141 (HUBBELL et al) and 3,438,754 (SHEPARD et al). OSTERHELD employs a spray coating of zinc on steel and a subsequent spray coating of aluminum on the zinc coating. HUBBELL et al and SHEPARD et al prepare the laminated sheet by vapor deposition of aluminum vapor upon a preformed galvanized steel sheet. Vapor deposition processes are expensive and difficult because of the low pressures required for volatilizing the aluminum vapor. The vapor deposited aluminum and the sprayed aluminum outer coating functions as an envelope over the galvanized steel sheet. Neither forms a zinc-aluminum eutectic bond.
Application of various coatings to molten zinc-rich metal coated steel sheets is known; asbestos fabric, U.S. Pat. No. 2,631,641, COFFMAN; glass fiber fabric, U.S. Pat. No. 3,615,276, SINGLETON.